Telescoping cylinders are used in various applications including hydraulic elevators. The principal reason for using telescoping cylinders with multiple plungers is to reduce the overall length of the cylinder assembly. In the case of hydraulic elevators this will allow reduction of the depth of the hole that has to be dug or make the digging of a hole unnecessary permitting installation of a "holeless" hydraulic elevator. One of the problems that has arisen in connection with the hydraulically synchronized telescopic cylinder is that each moving plunger has its own pressure chamber. Internal leakage or volume expansion of the fluid due to heat can result in relative movement of one of the plungers which will reduce the full stroke of movement of the assembly. U.S. Pat. No. 4,043,428, granted Aug. 23, 1977 to Otis Elevator Company, recognizes the aforesaid problem and makes use of a check valve incorporated between two of the pressure chambers. This valve can be opened by removing hydraulic pressure from all parts of the system. This is accomplished by lowering the elevator until all plungers are bottomed. This solution has disadvantages because the correction can only be made by lowering the elevator below the bottom landing. U.S. Pat. No. 4,357,995, granted Nov. 9, 1982 to Westinghouse Electric Corp. also recognizes the problem and provides a second oil pump connected to the inner plunger pressure chamber. When insufficient oil is detected in the pressure chamber, the second pump is activated to replenish the oil supply therein. This solution is undesirable since it cannot correct a condition wherein there is too much oil in the inner plunger pressure chamber.